Telephone system



June 1 1926.

E. H. CLARK TELEPHONE SYSTEM Filed Dec. 21, 1.922 2 Sheets-Sheet 1 /n ven for: Edgar/i Clark.

by A7731 June 1,192 1,586,518

E. H. CLARK TELEPHONE SYSTEM Filed Dec. 21, 1922 2 Sheets-Sheet 2 III II II 1| mvemar f/yar/z C/ark I electrically farthest from the incoming; sub-o Patented June 1, 19 26.'

DGAR H-'.ICIVJARK,;OELBQIGHMQI\T;D HILL, NEW QQRKsASSiGNORKTO :WESTER1\T ELEc-J TRiOGOMBAgNY;INCQREORATEDLOF NEW :yonxyn. VY.,=AV oonronnmxon on NEW:

YORK! TELEPHONEfsYSTEMLf Applicationlfiled nejce b t 21 111 92 seria nb. 608,139. a

This invention ife'lat'e's {to telephone sysi' s'appar tus. i Y. we i V I lit is the object of this nuent onj to evenly of over a plural ty common licity of construction and itsspeed;economy and re- IIe17etofo re, Qin such Systems. as j that: d sclosed in'the" Bititi'sh Pat'entNo; 183 5438, s; sued to lXVestern Electric, Company, Limited,

posed tfoassign a gmap of link circuits to a plurality of' subs'crlbe csl; (lines and to a'1'-" range the intermediate" apparatus in such a coming} lines, andj when such' link is found busy, to autoinaticallj transfer. the call to the next succeeding link. Itis apparent .in' such asysten that the link circuits 'elec- 1 trically nearest the incoming subscriber's lines Will he called uponto hand-lethe hulk of the tliatfic assigned; to the group iniwhich they are located, 'andj that the link circuits ;sci' ihei1-s; line W'ill remain relatively inactive.

Fi oin the foregoing, such a: system, ;the \;vear' one link circuit in a group Varies directly with itsfe'lectrical proximity to its associated inconnngfsubscriberst'lines. This unev n. Weafing effect will necessitate frequent repairingand adjustingofthe link cil 'cuits electrically near est the linesincoining to their respective groups. i

The foregolngfobgect of'this invention 1s obtained byftheprovision of a separate start ing conductorfor each hnefanda relayfor;

eachlgroup of links fof connecting eachof said starting conductors to afdiflerent one, of said links frolnwhence the selectijonof an idleli'nk by said lines mayvp'roceed.

teinplated by the present, invention will 'be,

clearly understood" from the following de tailedrdescription empty reference to the accompanying j draivingsfint which Fig. 1;

' shows two groups of incominglines with their respective, d stributing 'linki relays;

relays 24; C

it is e ident that in from the group's-shown inFig. 1' to the: outteius and particularly to coordlnat oingfttunk cifcuitssh'ownjon the right of J The-following description is'directed only to the operation of the circuits employed in of the [typeof mechanical apparatus" which may employed in connection with these-circuits finay be had fron lthe above switches; of thistvpe, huta clear understand 1 mentioned;Briti h Patent 4 N61; 183%38? of Gons deii' ng; the combined circuit. ar rangeinentjshown inFigs'. "land 2 the opeif ation is as follows 'Theifea e 'shown two groups of t'woqiin line 21 wishes to establisha connection. The follow ng description n will: showhow, uponthe removal of the receiver on line 21, the line will 1005 7 a N V "Thje ealling suhsciihe'rfon line 21 removes the i'eceiver fi'oni the switchhook and estab lis'hes' a' circuit for" the energization of line This circuit extends a from grounded hattel y," left-hand laygtbad: contact and outer armature of cut-ofi 'ielay 25 over the'closed loop of line 21, theinner armature and back contact ofgrelay '25fand thence "to ground through the i'ght-lhand Winding of line relay 24'.

'Tl e operation ofielay 24c establishes a circult ,fiQnig 'ounded battery, Winding ofver ticalline magnet 28, conductor 29, arinatuirean'd front contact o'fli ne i'elay 24-{Wind mg of relay 26fno1n1al niake-beforehreak conta'ctsiof ielayf26; conductor 27, conduw tor 30, back contact and: upper armature of relay back cont-act and upper' 31, conduct-o1" 32 to ground o-irei the armature of relay beautoniatically connected to trunk Winding of re- 3 1' Relay 26 energizes,finithis@circuit and 5 v in attracting its armatureestablishes acir- Other'features and'advantages' as are concuit which "may be traced from grounded battery, winding of vei tical line ,inagnet 28,

conductor 29, armatureand front contact of linelrelayi24e,'winding of i'elay 26, front coiitact and a fniatu 'e of relay 26', conductor 34,

' \v-inding pfrelay 31;, conductor: 32 to ground 7 over the hackcontact and I upper, armature of relay33r Relay '31 op eratesingthis circuit and-at its upper,armature interrupts the original energizing circuit for relay 26 and at its lower armature establishes an obvious circuit for the distributing link relay? 35. The operation of magnet 28 in the circuit previously traced rotates itsassociated line bar and prepares for operation the insulating pieces such as 3'6 shown in the vertical line above magnet Magnet 28 in attracting its armature closes a circuit from ground, front contact and inner left-hand armature of magnet 28, conductors 37 and 3,8,"back contact and outer left-hand armature of slow releasing relay 39, winding of trunk bar magnet 4:0 to battery and ground.

Magnet .40 causes the rotation of its asso- .ciated trunk bar and prepares for operation the insulating pieces such as ll common to the trunk bar and respectively individual to the several links. Magnet 40 in operating establishes a locking circuit for itself which extends from grounded battery, winding of magnet 10, inner armature and back contact of relay 4C2, front contact and innermost armature of magnet i0, conductor 37 to ground over the inner left-hand armature and front contact of magnet 28. This locking circuit is'nec'essary owing to the fact that upon the ener- -gization of magnet -10, a circuit is established from ground, middle armature and i frontcontact of magnet 4:0 to battery and ground through the winding of slow releasing relay'39 causin the operation of this relay and the opening of the original energizing circuit for magnet d0. V.

The operation of distributing link relay 85, as described, as a consequence otlthe operation of line relay 2 causes the attraction of its armatur'es, thereby connecting the windings ot the individual link magnets t8, it-l, l5 and 46 to the conductors 4C7, lS, 49 and 50, respectively, which in turn are adapted to extend these connectionsto ground at the outer left-hand armature of magnet 40 subsequent to the actuation of their respective associated line bar magnets such 2t 51 and Magnet having been operated upon the ls-nation of line'relay 2e completes a circuit extendin from ground, outer left-hand arn'iatnre and front contact of magnet lO, conductor 53, outer left-hand armature and trout contact of magnet 28, conductor 47, lowermost armature and front contact of distriimting link relay 35, armature and back contact of relay 5%, conductor 55 and thence to battery and ground through the winding of, individual link magnet 43. hlagnet 3 becomes energized in this circuit and causes the movement of the cards 36 and ll which, as hereinbefore described, have been conditioned for operation by the etnation oi the vertical magnets 28 and 40,

respectively. The actuation of the cards 36 and 41 effects the establishment of a circuit from the line conductors 56, 57 and 58 leading from station 21 through the link conductors- 59, (30 and 61, respectively, to the trunk conductors 62, and 614;, respectively. A circuit is now established from ground, front contact and right-hand armature of slow releasing relay 39, through conductor (i l, link conductor 61, line conductor 58 to battery and ground through the winding of cut-oii relay 25. A circuit may also" be traced from ground on link conductor 61 over conductor 65, winding of relay 5%, conductor 55 through the winding of individual links magnet 43 to battery and ground, this circuit forming a means -tor maintaining magnet 43 operated during the use of the talking circuit. Relay 54:, however, does not become immediately energized in this circuit due to the fact that its winding is short circuited by the extension of ground from the armature of the trunk bar magnet as hereinbefore described.

pon the energization of cut-otl relay 25, line relay 2a becomes deenergized, resulting in the deenergization of relays 26, 31 and 35 and magnet 28, whereupon the short circuit about the winding of relay 5% being removed this relay becomes energized and transfers the control of conductor l? from magnet to magnet 4-1.

As soon as the line 21 is extended through to the trunk 100 acircuit through winding of relay 42 is completed over the substation loop and this relay remains energized during the establishment of the connection. Relay42 opens the locking circuit for magnet -lO which releases a switch bar associated therewith. Relay also maintains relay 39 operated by placing a ground on the winding of relay 39 as a substitute for the original ground placed thereby the middle armature ofmagnet 4L0. he connection between line 21 and trunk 100 is maintained by the continued energization of relay 39 which controls the link bar serving the linkiUl.

ll' hen the subscriber on line 21 replaces his receiver on the switchhook and opens the loop of this line, relay 42 becomes energized and shortly thereafter relay as retracts its arinutures removing gromid from conductor 64, allowing magnet d3, relay and cut-oft relay 25 to become dcenergized, whereupon the connections are restored to norn' ah i \Vhen trunk 100 is toundbusy relay 39 is energized so that a second call initiated in any subgroup of lines will seize trunk 105 through a circuit extending through the innermost armature and back contact of magnet 4&0, inner left-hand armature and front contact of relay 39, back contact and outer left-hand armature of relay to battery and ground through the winding oi" magnetfiG. The mag-net'ZG functions in manner similar to n1 agnet 4 0 ashereinbe-fore described, j j

It is to be noted tliat when relay 54,13 energized in the locking circuit ,for i'nagnet 43 in the" connection 'justdescribed a callemanating from line20- Which-Would effect;

' the operation of the vertical line magnet 70 form one di italsub 'rou and second. the

would, be handled overconductor l7- asbe-1 tore but the circuit for. magnet 43' onldibe foundgopen at the back contact of relayo; whereupon thelconnection Would be transfcrred to, link 102 by the energization of magnet e4 over the armature and front contactof relay and armature an'dgback 0on5 tactot' relay Itis to loe further apprehended froin'the disclosure that calls ema-J natingfrom stations 20 and21' havingfao cessto vertical line magnets 28- and. 70: ill normally be handled overthe link circuit 101;. Furthermore, calls "emanating from stations having the line relays 91 and 92; having: access'to magnets 51 a1nd'93,'Willnor mally belhandledover link 102, and calls originating from the station havingline relay 9-l--,-liavingaecess-to the-vertical line inag net; 52 will normally behandledover link 103. The same procedure Will apply in handling calls over the other various links in the group,'and is also applicable to the loiver'group oflinks shown inFig.' 2 1 By givingjpreference to the various linesin a group for a selection of a link circuit over which to complete aconnection,it is evident that. no one link will be'called upon to handleeach call, incoining'ifronrthe,sta}

tions served by a group including thislink, but that the trallic :Will be distributed sub stantially evenly over the various links'iin the group: j I a p some of the general features-oi this systeni which are; included in the aforesaid' British patent are: First, the'lines in'a ver-fl tical or longitudinal ro-W alcove magnet 28 lines in a horizontal or transverse row to theright of the group oi magnets l3 to 46; form anothcrdigltal subgroup. These subgroups} may belsaid to he inithe two principal direcare, however, divided into groups and-each remaining units d1 git.

two coordinate system,thusthegroup of link i circuits including links 101, 102,103 and 104,

contact sets, .o'newbefore eaclilin'el and trunlt tionsof a two coordinate systenn and, hence,

in a one-hundred line maingroup there Will be twenty digital subgroups, ten of which will be characterized bya tens digit, and the 77 ten will" be characterized by a All the link circuitshave access to the trunks such 100 and 105. The link circuits group oflink circuits is individual to a par--v ticular group ofjlinesinonedirection oithe is individual to the particular group contain ing lines 20 and 21, etc. ZIIId'fOIDIS aarow' ofniagnets 70, 1 51,

I ample; lines 21 and same magnet 28 callsimultaneously;the 'con- 1 .nection-of both lines to thesaine t-runk an; 'cuit' through' different link circuits is pre *tion ofrelay 31 Thus if lines ated" 1 gizing cir'cuit ofrela y 98.

ofi the'se'linksthough available-to each of these lines is initially assigned tov certain" lines 1 nieac lr group, for instance, the link 103 is initially assigned to?" calls emanating from th'estation-associated with linerelay' 9%, that p is, a call originating atthis station willbe handled-lover the link l03 whenever this 'link is idle instead of first testing the links 101 and' 102;for tlieiiiidle or-busy' condition.

I .lit shouldheffurther noted that-Inagnet'QS upon energizing. opens" its outer right-hand armature contactsand removes liatte'ryfpo- V .tential front the Winding of all other n1agnets I corresponding to. i'nagi'iet- 28', such as .93 and 52,f.etc., serving other 'linesaoilthe same or other subgroups,

possible for two such magnets to becoineen-r ergized atithe sanie 11116," the magnet nearest the sourceof' potential being'given the prel e erence. .q

Iftwo lines/in different groups, for' e'iz- 23 bothfse'rved' the vented since it is i not possiblefor link jloar magnets such was and serving respeoj tivelytlie groups of lines in Whichlines' 21 and28 terminateto become sin'lultaneonsly operated. The simultaneous operations of magnets 4-3 and95 durmg tlie operation of trunkbar inagnet 40 i (such operations would permit lines 21" and 23 toi be sii'i'iulta-neously connectedto trunk )a re preventedby the operatlQn" of relaf 3 which g 7 its upper armature opensfthe initialenergizing circuit for relay 26- Whiclr controls the opera simultaneously initiate'calls, line 23 will have the prefer-elite, but if line2l initiates a all just a small fraction of a secondprior to line andnill ha-ve opened the initial one" .Froin theforegoing 'description it is obvioustha-t' the circuit arrangement disclosed herein provides for, a substantiallyeven distribution of calls overthe various lii'ik 'circluits in a group, and figuring on the basis that-the calls to he'handl'ed over'a group-of link circuits will emanate from the various stations assigned" to thegroup velf-links substa ntially 1n" rotation-the distribution of link; circuits-will be'eve'ni a What isclailned is:

example,- lines 20 and 22 so that shouldupon ani In" like manner the remain 2i and 23 lilo 23, relay 31' Will'have become oper' 1. In a telephone system, a plurality of lines, a group of link circuits, a relay coinmon to all of said lines, a plurality of contacts controlled by said relay, each of said contactsbeing individual to oneot said lines, and relay for each 01"" said lines adapted to include its associated contact in a circuit to select one ozt'said link circuits "for coopera tion with one of said lines subsequent to the operation of said first relay. I

2. In a telephone system,a group of lines divided into sub-groups, a group of link circuits, a line magnet for each line in a subgroup, a relay common to all links in a group and having a plurality of contacts controlled thereby, each of said contacts being individual to a sub-group of lines and to a link circuit in said group, and means eliective upon the conjoint operation of one of said line magnets and saidrelay for connecting the line associated with the operated line magnetto the link circuit corresponding to the contact individual to the subgroupoi' lines in which said'line is located.

3. The combination with a plurality of groups of line extending linksot' a plurality of conductors equal in number to the links in said groups, a relay individual to each each of said conductors being arranged normally control a particular one of said of said groups for extending said conductors into operative relation with said groups,

links, and Ineans ior transferring the con t-rol of each of said conductors to the other links of the group.

l. The combination with a plurality of groups of line extending links of aplurality of conductors equal in number to the links in each of said groups, a plurality of lines, operating means for each of said lines associated with said conductors, means individual to each of said groups for extending said conductors into operative relation with said groups, each of said conductors being arranged to normally control a particular one of said links, means effective upon the joint operation oi one of said operating means and last mentioned means for connecting one of said lines to a preselected link, and means for transferring the connection to the other links in a group.

5. The combination with a plurality of groups of line extending links of an advanced starter wire circuit for each of said groups, a pluralityof conductors common to said groups for entering and controlling said starter wire circuit at various points thereof, and means individual to each of said groups for operatively associating said conductors with said starter wire circuit.

6. The combination in a switching system of a plurality of lines, operating means for said lines, a group of link circuits, operating means for each link in said group, a plurality of conductors, one t'or each of said link circuits, and means for connecting each oi said conductors into operative relation with its respective link circuit and adapted to cooperate with said first operating means in effecting the operation of said second operating means to etlect the connection of one or said lines with a certain one of said link circuits.

7. The combination in a-switching system of a plurality of lines, operating means for said lines, a group of link circuits, operating neans for each link in said group, a plurality of conductors, one for each of said link circuits and a relay controlling a plurality of contacts tor connecting each of said conductors into operative relation with its respective link circuit and adapted to cooperate with said first operating means in effecting the operation of said second operating means to eti'ect the connection of one of said lines with a certain one of said link circuits.

r 8. The combination in a switching system ot-a plurality of lines, operating means for said lines, a group of link circuits, operating 'lliGLllS tor eachlink in said group, a plugroups of lines, and a plurality of groups of link circuits, each of said groups of link circuits serving a corresponding group of lines, each of said links being normally assigned to one of said lines, and each line in each group having preference to a ditl'erent link in its corresponding group oi? link circuits, and all of said links in each group being successively accessible to each line in its corresponding group of lines.

10. In a telephone system, the combination of a plurality of incoming lines, switch having a group of link circuits, each or said links being normally assigned to one of said lines, a plurality of contact sets for each of said link circuits, switching members cooperating with each other, each switching member serving plurality of contact sets, means for operating said switching members, and ineans'tor connecting one of said lines with its normally assigned link circuit and transferring the connection successively to the succeeding links in said group when the normally assigned link is busy, subsequent to the actuation of said first mentioned means.

11. In a telephone system, lines, a switch hevinglinks for extending said lines, a con ductor for each of said lines, a chain starting circuit for stud links, and a single relay for connecting saidcon'ductors to different [points 111 said chaln-starting cn'cult froln tor for each of said lines, a chain-starting circuit for each group of links, and a relay for each. gi'on p'of links for connecting each of saidconductors to a different point in the chain-starting circuit of the group of links associatedwith said relay from whence the selectionlof an idlelink in'each group may proceed;

I In witness whereof, I hereunto subscribe i 7 may name this 18th day ofDecembenA. D.

EDGARI-I; CLARK. 

